The invention relates to a rotor body, in particular for the rotor of the starter or the starter-generator of an internal combustion engine, with the characteristics mentioned in the preamble of claim 1.
Rotor bodies of this generic type are known. Rotor bodies of this kind can be components of an electric motor which in turn is a component of a starter for the motor of an internal combustion engine.
The electric motors used to start internal combustion engines are direct-current motors, alternating current motors, and rotary current motors. The electrical direct-current inverse-speed motor is particularly suitable for use as a starter motor since it produces the high initial torque required to overcome the initial rotation resistance and to accelerate the [drivetrain] masses.
The torque of the starter is predominantly transmitted via a pinion and a ring gear to the flywheel on the crankshaft of the internal combustion engine. Occasionally, though, V-belts, toothed belts, chains or direct transmission to the crankshaft are also chosen. However, due to the high ratio of transmission between the starter pinion and the ring gear of the motor disk flywheel, the pinion starter is best suited for a starting procedure since it can be designed for a lower torque at high speeds. This design makes it possible to keep the dimensions and weight of the starter down.
In addition to starters of this kind, so-called starter-generators are also known, which can be used as the starter for the internal combustion engine, as a drive motor of the vehicle, and as generators.
The coupling with the internal combustion engine and/or a transmission as well as the disposition of such starter-generators can differ from the simple starter due to the expanded intended application.
However, such starter-generators frequently have a rotor body of the type that defines the species.
The form of the rotor body of this generic type is frequently complex. This can depend, for example, on screw-connecting pieces to be provided, to which an intermediary clutch flange can be fastened. This complex form of the rotor body has the disadvantage that the rotor body production is very costly because it is only possible through a combination of turning, milling and/or stamping processes executed on one and the same work piece. The production of the rotor body is therefore time-consuming, costly, and in addition, a large quantity of waste is generated during production.
The rotor body according to the invention can be produced comparatively simply and therefore inexpensively. Because the rotor body is comprised of a rotationally symmetrical base body, which constitutes the hub, and one or more lamellas, which each have a continuously uniform thickness in the direction of the rotational axis of the rotor, the individual components of the rotor can be at least predominantly produced by means of a single machining method which is particularly suited for the respective form.
The rotor body design according to the invention is particularly advantageous if it is a non-rotationally symmetrical rotor body which would be particularly expensive to produce by means of known machining methods.
The production of the rotationally symmetrical base body which constitutes the hub can take place, for example, by means of turning.
However, it is likewise conceivable to produce the hub as a stamped, drawn, and bent part which can, for example, be riveted to the lamellas.
The term xe2x80x9crotationally symmetricalxe2x80x9d should not be understood here in the strictly mathematical sense, but rather with regard to the machining method used, so that for example bores which are provided at separate locations on a base body produced by turning do not absolutely have to be symmetrical.
The lamellas can be stamp-bundled or can be individually produced lamellas. The use of stamp-bundled lamellas, which can be comprised of a number of congruent plates produced by means of stamping, permits a particularly inexpensive production.
Optionally, the base body can also be a stamp-bundled part so that as a whole, there is a total of one bundled unit after assembly of the rotor.
In order to assemble the rotor body, it is necessary that the individual lamellas be connected to the base body. If one or more of the individual lamellas is in the form of stamp-bundled lamellas, the individual lamellas can first be assembled using suitable connecting means and then can be connected to the base body. It is likewise conceivable for both the individual lamella components and the base body to be connected using the same connecting means.
These connecting means can, for example, be constituted by screws and/or pins and/or bolts and/or rivets.
Preferably, the outer circumference region of the rotor body is constituted by one or more lamellas. The rotor winding, which as a rule is provided on the outer circumference region, can then be disposed directly on the lamella or lamellas.
The transmission of force from the rotor body to the clutch then preferably takes place directly by means of one or more lamellas so that the connection between the base body and the lamellas is only subjected to a smaller amount of stress than would be the case if the force were to be transmitted from the lamellas into the base body and from there into the clutch.
For purposes of the above-mentioned transmission of force, one or more lamellas preferably constitute a connecting region which is provided for connecting the rotor body to at least one clutch element.
A clutch element can, for example, be constituted by an intermediary clutch flange. Alternatively, or in addition, the clutch element can also, for example, be constituted by a clutch thrust plate, where the specific design of the clutch elements can depend, for example, on the starter type.
A reinforcing ring can be provided to protect the rotor winding. This reinforcing ring is connected to the rotor body by connecting means, wherein these connecting means can either be constituted by the connecting means used to connect the rotor components or can be separate from them. The reinforcing ring itself can either be a deep-drawn part or a formed part.
For the case in which it is a short circuit rotor that represents a cage rotor, the short circuit cage, which is used in this type of rotor and is comprised of rods and short circuit rings or can be embodied of one piece, constitutes the rotor winding.
The outer circumference of the rotor body is preferably cylindrical wherein for example, two essentially annular lamellas can each constitute a section of this outer circumference.
At least one of the lamellas is preferably connected to the base body.
If three essentially annular lamellas are provided, each of which constitutes a section of the cylindrical outer circumference region of the rotor body, preferably only the middle lamella is connected to the base body, where in this instance, the lamellas are interconnected through the use of connecting means which can simultaneously be used for the attachment of the above-mentioned reinforcing ring.
If teeth serving as a pulse generator are provided, they are preferably constituted by the inner geometry of at least one essentially annular lamella.
Depending upon the embodiment, adjusting springs or similarly acting means can be provided to encourage the torque transmission between the individual rotor body components; for reasons relating to cost and weight, they should only be used if the specific embodiment actually requires it.
The above-mentioned and additional advantageous embodiments and modifications of the invention ensue from the dependent claims.